If you have intercourse during menstruation and have an orgasm, the uterus will also be in a state of excitement, which will cause contractions of the uterus. After contraction, the menstrual blood in the uterine cavity will enter the pelvic cavity along the fallopian tubes, which may lead to endometriosis. In addition, intercourse during menstruation may cause damage to the mucous membrane of the cervix, so that pathogenic bacteria may enter the cervix along the damaged fissure and cause chronic inflammation of the cervix. Therefore, it is not allowed to have intercourse during menstruation. Intercourse during menstruation can also lead to endometritis and even pelvic inflammatory disease. So do not have sex during menstruation to avoid causing some gynecological diseases.